This invention relates to a device for testing the preferred or strongest magnetic orientation in a recording surface. More particularly, this invention relates to a circular or ring-type magnetic transducer having a rotating spindle where the spindle carried an element of magnetic material longitudinally oriented on the face thereof so that the transducer presents to the recording medium being tested a continually varying orientation.
In manufacturing magnetic recording material, certain production processes have been found to produce a recording medium with a preferred magnetic orientation where the medium is most responsive to recording signals and easiest to read. It is desirable in recording media to have the preferred magnetic orientation be in a direction favorable for reading and writing based on the direction of movement of material relative to the recording and reading transducer as well as least favorable for interference between recorded materials which are closely positioned to one another but should not cause interference. One such type of material is a magnetic disk of the type used in data processing equipment. Such a disk contains numerous tracks for recording data which are arranged radially on the disk and each track is concentric with all the others. The disk rotates with respect to the transducing head and so the preferred orientation for reading and writing should be with the rotational direction of the recording media while adjacent concentric tracks radially located from each other should be against the preferred orientation of the media so that interference is minimized.
Thus, in the manufacture of disk packs for data processing equipment, various testing procedures are necessary to spot test processes used for placing the magnetic media on the disks to insure that the processing is producing the desired results. Typical prior art testing techniques required completion of a disk device and testing by actual recording and reading of the disk and comparison with a standard result obtained with the process. Thus, no actual measurement of the disk magnetic orientation was possible during manufacture but rather a testing of the performance of the disk after manufacture. It is, therefore, desirable to provide a method and device which may be used to actually detect the preferred magnetic orientation of a recording medium.